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Hobbico Avistar C.G. Range...

Using the Great Planes C.G. Machine, my Avistar is balanced at 2.75 ".
Here is my problem:
The instructions that came with the plane suggest the C.G. is @ 3.25" for your "first flights".
Another place I read, it says the C.G. Range is between 2.5" & 3.5".

Should I really be concerned where my C.G. is at or should I add weight to bring it to the 3.25" mark?

Hobbico Avistar C.G. Range...

Tower's specs list the CG range between 3 5/8" to 4 1/2" back from the leading edge with 3 5/8" as a docile starting point.
At 2 3/4" your a little nose heavy which will probably be OK but it might make flaring for a nice landing a little more difficult. Have you tried moving the battery a little further back?

Hobbico Avistar C.G. Range...

I haven't checked Towers web site but I built 2 of these last summer and I saved the manuals so I dug them out and checked. The manual says "The balance point is located 3-1/4" (83mm) back from the leading edge. This is the point at which your model should balance for your first flights. Later, you may experiment by shifting the balance up to 5/16" (8mm) forward or back to change the flying characteristics". It also recommends not exceeding the stated cg range. I balanced both planes at the 3-1/4" mark and both planes flew excellent and handled perfectly. I was pretty impressed with the overall quality of the planes.

Hobbico Avistar C.G. Range...

Sorry I did forget to mention that I added about 1/4 to a 1/2oz of lead to the tail of the plane to get it to balance on the recommended cg. I cut a 1" opening in the fuse ahead of the stab, coated the weight with epoxy and glued it in. Covered te hole with a scrap of Monokote.

Hobbico Avistar C.G. Range...

I just don't understand....
I buy an ARF version of a plane, build it as specified in the instructions, make absolutely no alterations and yet we have to add .25 - .5 oz of weight to get it properly balanced.
Very frustrating.

EDIT: I also just emailed Hobbico with the problem... lets see what they say.

Hobbico Avistar C.G. Range...

I had the same problem with mine. It flies great with the OS46FX that I mounted, but there is enough lead in the tail you can use it as a weapon. During training, the tail was broken off on one of my better take off's. Pulled back on the throttle when it was about 5 ft off the ground instead of the elevator, snapped the tail right off when it hit. Was able to fix it and have used it for the last year. Still have the weight though.